Change from 2-way to 3-way switching with conditions

[TTbangbang]

Hello,

I haven't been able to sit down and think this one through yet, and I wondered if anybody would come up with something I wouldn't have thought about if I had. Jeez, I should just get to the question! headbang

How would you change a two-way switching situation [T&E from terminals 5 and 7 at the light point to a two-way switch, and a 3 core cable from this switch to the second two-way switch] to a 3 switches situation when you cannot run a further cable to either of the existing two way switches, but you can access the light point?

Many thanks for any advice on this.

TTbb

 

[sellers]

I dont think its possible. Just had a quick draw on a bit of paper, and its not looking good.

If its possible attatch your 3core onto the existing t+e and pull it up the wall. Then put the t+e down to the new switch with your 3 core.

 

[a1]

I pretty certain that this has been discussed on here?

Where's our Patch?

 

[SPECIAL LOCATION]

Hello,I haven't been able to sit down and think this one through yet, and I wondered if anybody would come up with something I wouldn't have thought about if I had. Jeez, I should just get to the question! headbang

How would you change a two-way switching situation [T&E from terminals 5 and 7 at the light point to a two-way switch, and a 3 core cable from this switch to the second two-way switch] to a 3 switches situation when you cannot run a further cable to either of the existing two way switches, but you can access the light point?

Many thanks for any advice on this.

TTbb

You have GOT to make connections to the other switches.

i.e. At every switch point there has got to be two possible circuit paths that the current can flow,

and at every one of the switches the two optional paths can be reversed over!

 

[batty]

I pretty certain that this has been discussed on here?Where's our Patch?

It was the one when his mate had wired job up but forgot to two way for down on the landing I think the injuns getting lazy.

Batty

 

[TTbangbang]

Many thanks for your replies. I had a go at this on paper last night and found that...

- adding a one way from the light terminals wouldn't work

- breaking into the return switch wire, to add a switch, to terminal 7 wouldn't work

... so went to bed and at 2am woke up with an idea: break into the 3 core between the two existing switches and add an intermediate switch (sorry I didn't say that the 3 core would be accessible in the ceiling void BlushingBlushing I can feel you jumping on me in outrage!). This would require two connector blocks/ junction boxes at each broken end then 3 core from each to the intermediate switch - a bit dodgy no?

Why I didn't think of this before I don't know headbangheadbangheadbang (...well I do, I'm obviously a bit slow!).

Are there any issues about using this method? [Apart from making the connections accessible]

TTbb

 

[Apache]

Many thanks for your replies. I had a go at this on paper last night and found that... - adding a one way from the light terminals wouldn't work

- breaking into the return switch wire, to add a switch, to terminal 7 wouldn't work

... so went to bed and at 2am woke up with an idea: break into the 3 core between the two existing switches and add an intermediate switch (sorry I didn't say that the 3 core would be accessible in the ceiling void BlushingBlushing I can feel you jumping on me in outrage!). This would require two connector blocks/ junction boxes at each broken end then 3 core from each to the intermediate switch - a bit dodgy no?

Why I didn't think of this before I don't know headbangheadbangheadbang (...well I do, I'm obviously a bit slow!).

Are there any issues about using this method? [Apart from making the connections accessible]

TTbb

Wago's are a permanent joint so don't need to be accessible!

 

[Apache]

It was the one when his mate had wired job up but forgot to two way for down on the landing I think the injuns getting lazy.Batty

I had a lot on last night. I will look later!

 

[user 6351]

I may have mis-counted here ttbb... but I read your last post as you've got two way switching with a three core plus earth between the two switches?

If so, then you are still a wire short even if you break this to put in an intermediate as you need four wires at the intermediate switch.

Or... have you put singles in at either end, and just a t&e strapper between the switches? If this is the case, then yes, you laughing as you can just break in to this and add the intermediate.

 

[anwah]

If he breaks into the 3 core and earth between the switches he will have 6 wires

plus the 2 earths. He would only need to cut the 2 wires that are being used for the strappers.

 

[green-hornet]

If he breaks into the 3 core and earth between the switches he will have 6 wires plus the 2 earths. He would only need to cut the 2 wires that are being used for the strappers.

You would need 4 wires for an intermediate switch.

Normal practice would be to crimp the live (common) then run the strappers down with the earths to the switch.

The junction box above could be a single gang pattress box with a blank over it, connections done in push fit connectors do not require maintenance, and the lid can be marked to indicate exactly what this junction box is for.

 

[TTbangbang]

You would need 4 wires for an intermediate switch.Normal practice would be to crimp the live (common) then run the strappers down with the earths to the switch.

The junction box above could be a single gang pattress box with a blank over it, connections done in push fit connectors do not require maintenance, and the lid can be marked to indicate exactly what this junction box is for.

That's the way I was thinking of doing it. Talking of leaving messages under floorboards, I once found a cigarette packet (no cigs ) with the name of the bricklayer, the current prime minister (M.Thatcher) and the cost of the packet written on it. Sounds a nice idea, leaving something historical behind

TTbb

 

[kme]

If the 3+E had NOT been accessible, for future reference, there IS still a way of doing this.

http://www.tlc-direct.co.uk/Main_Index/Lighting_External_Index/Lighting_Garden_and_Lantern_Index/EasySwitch/index.html

(they can be set to "toggle" mode)

 

[user 6351]

Good point Anwah, and it's a good job that one of us can count!

Sorry ttbb... can I put it down to friday & a long week?!?